Light observation device, imaging device used for same, and light observation method

ABSTRACT

A light observation device has a light splitting optical system for splitting observation light of an observation object; an imaging lens for focusing split beams to form optical images thereof; an imaging device arranged at image formation positions of the two optical images and being capable of performing independent rolling readout in a pixel row group included in a region corresponding to the image formation position of one optical image and in a pixel row group included in a region corresponding to the image formation position of the other optical image; and a control unit for independently controlling the rolling readout in the one pixel row group and in the other pixel row group; the control unit performs control such that a direction of the rolling readout in the one pixel row group and a direction of the rolling readout in the other pixel row group are identical.

TECHNICAL FIELD

The present invention relates to a light observation device forobserving a optical image of an object, an imaging device used for thesame, and a light observation method.

BACKGROUND ART

In the technical field of life science or the like, it is commonpractice to disperse observation light (e.g., fluorescence or the like)from a specimen according to wavelengths and observe a plurality ofoptical images resulting from the dispersion. For example, Non PatentLiterature 1 below discloses the dual view microscopy technique with asingle camera, and describes this technique such that the observationlight is dispersed by means of a light splitting assembly attachedoutside a microscope main body and that two observation beams resultingfrom the dispersion can be imaged with use of the camera. PatentLiterature 1 and Patent Literature 2 below disclose the light splittingoptical systems to be used in the dual view inspection technique.

CITATION LIST Patent Literatures

Patent Literature 1: U.S. Pat. No. 5,926,283

Patent Literature 2: U.S. Pat. No. 7,667,761

Non Patent Literature

Non Patent Literature 1: K. Kinosita, Jr. et al., “Dual View Microscopywith a Single Camera: Real-Time Imaging of Molecular Orientations andCalcium,” The Journal of Cell Biology, Volume 115, Number 1, October1991, pp 67-73

SUMMARY OF INVENTION Technical Problem

However, since the foregoing conventional microscopy technique is toobserve two types of optical images with the single camera, when thecamera was one adopting the rolling readout method, such as a CMOScamera, imaging timings at a specific part in the two types of opticalimages might be different from each other. As a result, comparativeobservation tended to be difficult between the two types of opticalimages from an object of a specimen.

Therefore, the present invention has been accomplished in view of theabove-described problem and it is an object of the present invention toprovide a light observation device which facilitates the comparativeobservation between two types of optical images from an object even inthe case adopting the rolling readout method, an imaging device used forthe same, and a light observation method.

Solution to Problem

In order to solve the above problem, a light observation deviceaccording to one embodiment of the present invention comprises: a lightsplitting optical system configured to receive observation light of anobject from the outside and split the observation light into first andsecond beams; an imaging lens configured to receive the first and secondbeams and focus the first and second beams to form first and secondoptical images; an imaging element which is arranged at image formationpositions of the first and second optical images, which is configuredwith a plurality of pixel rows including a plurality of pixels and beingarranged in juxtaposition, and which can perform independent rollingreadout in a first pixel row group among a plurality of pixel rowsincluded in a first region corresponding to the image formation positionof the first optical image and in a second pixel row group among aplurality of pixel rows included in a second region corresponding to theimage formation position of the second optical image; and a control unitconfigured to control the rolling readout in the first pixel row groupincluded in the first region and in the second pixel row group includedin the second region, wherein the control unit performs control suchthat a direction of the rolling readout in the first pixel row group anda direction of the rolling readout in the second pixel row group areidentical in a juxtaposition direction of the plurality of pixel rows.

As another aspect, a light observation method of another embodiment ofthe present invention is a light observation method using an imagingdevice which has a first pixel row group configured with a plurality ofpixel rows including a plurality of pixels and being arranged injuxtaposition, and a second pixel row group adjoining the first pixelrow group and configured with a plurality of pixel rows including aplurality of pixels and being arranged in juxtaposition and which canperform rolling readout in each of the first pixel row group and thesecond pixel row group, the light observation method comprising:splitting observation light of an object from the outside into first andsecond beams; focusing the first beam to form a first optical image soas to impinge on the first pixel row group; focusing the second beam toform a second optical image so as to impinge on the second pixel rowgroup; and performing control such that a direction of the rollingreadout in the first pixel row group and a direction of the rollingreadout in the second pixel row group are identical in a juxtapositiondirection of the plurality of pixel rows.

According to the light observation device and light observation methodas described above, the observation light of the object is split intothe first and second beams, the split first and second beams are focusedto form the first and second optical images, the first optical image isreceived by the first pixel row group included in the first region ofthe imaging element, and the second optical image is received by thesecond pixel row group included in the second region of the imagingelement. Then, detection signals of the first and second optical imagesare read out by the independent rolling readout from the first andsecond pixel row groups, respectively, while the direction of therolling readout in the first pixel row group and the direction of therolling readout in the second pixel row group are made identical. Thismakes it easier to match exposure timings at the same part of the objectbetween a detected image of the first optical image and a detected imageof the second optical image and thus allows exposure conditions for eachpart of the two optical images to be made uniform. As a result, it canfacilitate the comparative observation using the detected images of thetwo optical images.

Furthermore, an imaging device according to one embodiment of thepresent invention is an imaging device to be used for a lightobservation device which splits observation light of an object from theoutside into first and second beams and which simultaneously capturesfirst and second optical images generated based on the first and secondbeams, the imaging device comprising: a first pixel row group configuredwith a plurality of pixel rows including a plurality of pixels and beingarranged in juxtaposition; a second pixel row group adjoining the firstpixel row group and configured with a plurality of pixel rows includinga plurality of pixels and being arranged in juxtaposition; a firstsignal readout circuit for processing signal readout from the firstpixel row group; and a second signal readout circuit for processingsignal readout from the second pixel row group, independently of thefirst signal readout circuit, wherein the first signal readout circuitprocesses the signal readout in the first pixel row group by rollingreadout and sets a direction of the rolling readout to one direction ina juxtaposition direction of the plurality of pixel rows, and whereinthe second signal readout circuit processes the signal readout in thesecond pixel row group by rolling readout and sets a direction of therolling readout to the one direction in the juxtaposition direction ofthe plurality of pixel rows.

According to the imaging device as described above, the first opticalimage formed based on the first beam split off from the observationlight of the object is allowed to be received by the first pixel rowgroup included in the first region of the imaging device. At the sametime as it, the second optical image formed based on the second beamsplit off from the observation light of the object is allowed to bereceived by the second pixel row group included in the second region ofthe imaging device. Then, detection signals of the first and secondoptical images are read out by the independent rolling readout from thefirst and second pixel row groups by the first and second signal readoutcircuits, respectively, while the direction of the rolling readout inthe first pixel row group and the direction of the rolling readout inthe second pixel rows are made identical. This makes it easier to matchexposure timings at the same part of the object between a detected imageof the first optical image and a detected image of the second opticalimage and thus allows the exposure conditions for each part of the twooptical images to be made uniform. As a result, it can facilitate thecomparative observation using the detected images of the two opticalimages.

Advantageous Effects of Invention

According to the present invention, the comparative observation betweenthe two types of optical images of the object is facilitated even in thecase adopting the rolling readout method.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic configuration diagram of a light observationdevice 1 according to one embodiment of the present invention.

FIG. 2 is a perspective view showing an example of a configuration of alight splitting optical device 7 in FIG. 1.

FIG. 3 is a block diagram showing a configuration of an imaging device 8in FIG. 1.

FIG. 4 is a drawing conceptually showing directions of rolling readoutin pixel row groups 47 a, 47 b on a light receiving surface 41controlled by a control unit 9 in FIG. 1.

FIG. 5 is a drawing conceptually showing directions of rolling readoutin the pixel row groups 47 a, 47 b on the light receiving surface 41controlled by the control unit 9 in FIG. 1,

FIG. 6 is a flowchart showing a procedure of a light observation methodaccording to the embodiment of the present invention.

FIG. 7(a) is a drawing conceptually showing directions of rollingreadout on the light receiving surface 41 controlled by the control unit9 in use in a double view mode, and FIG. 7(b) a drawing showing exposuretimings in respective pixel rows 46 on the light receiving surface 41corresponding to the foregoing control.

FIG. 8(a) is a drawing conceptually showing directions of rollingreadout on the light receiving surface 41 controlled by the control unit9 in use in a single view mode, and FIG. 8(b) a drawing showing exposuretimings in the respective pixel rows 46 on the light receiving surface41 corresponding to the foregoing control.

FIG. 9 is a drawing conceptually showing directions of rolling readoutin the pixel row groups 47 a, 47 b on the light receiving surface 41controlled by the control unit 9 according to a modification example ofthe present invention.

FIG. 10 is a drawing conceptually showing directions of rolling readoutin the pixel row groups 47 a, 47 b on the light receiving surface 41controlled by the control unit 9 according to the modification exampleof the present invention.

FIG. 11(a) is a drawing conceptually showing directions of rollingreadout on the light receiving surface 41 in a modification example ofthe present invention, and FIG. 11(b) a drawing showing exposure timingsin the respective pixel rows 46 on the light receiving surface 41corresponding to the foregoing control.

FIG. 12(a) is a drawing conceptually showing directions of rollingreadout on the light receiving surface 41 in a comparative example, andFIG. 12(b) a drawing showing exposure timings in the respective pixelrows 46 on the light receiving surface 41 corresponding to the foregoingcontrol.

FIG. 13(a) is a drawing conceptually showing directions of rollingreadout on the light receiving surface 41 in a conventional example, andFIG. 13(b) a drawing showing exposure timings in the respective pixelrows 46 on the light receiving surface 41 corresponding to the foregoingcontrol.

FIG. 14(a) is a drawing conceptually showing directions of rollingreadout on the light receiving surface 41 in a comparative example, andFIG. 14(b) a drawing showing exposure timings in the respective pixelrows 46 on the light receiving surface 41 corresponding to the foregoingcontrol.

DESCRIPTION OF EMBODIMENTS

Embodiments of the light observation device and the imaging device usedfor the same according to the present invention will be described belowin detail with reference to the accompanying drawings. In thedescription of the drawings the same elements will be denoted by thesame reference signs, without redundant description. It should be notedthat each drawing was prepared for description's sake and is depictedwith particular emphasis on a target part of description. For thisreason, dimensional ratios of respective members in the drawings do notalways coincide with actual ones.

FIG. 1 is a schematic configuration diagram of the light observationdevice 1 according to one embodiment of the present invention. The lightobservation device 1 according to the present embodiment is a devicethat splits observation light of an observation object A into wavelengthcomponents and that captures and outputs optical images of the split twowavelength components. As shown in the same figure, the lightobservation device 1 is configured including: a stage 2 on which theobservation object A is to be mounted; a light source 3 which emitsillumination light I to be applied onto the observation object A; acollimator lens 4 which condenses the illumination light I emitted fromthe light source 3; an objective lens 5 which condenses observationlight B₁ such as fluorescence or reflection generated from theobservation object A in accordance with the application with theillumination light I; a beam splitter 6 which reflects the illuminationlight I from the light source 3 toward the observation object A on thestage 2 and which transmits the observation light B₁ from theobservation object A; a light splitting optical device 7 which splitsthe observation light B₁ into two beams and which outputs two opticalimages; an imaging device (imaging element) 8 which is arranged at imageformation positions of the two optical images split by the lightsplitting optical device 7; and a control unit 9 which controls theoperation of the imaging device 8. This light splitting optical device 7is internally equipped with an aperture stop 10, a collimator lens 11, alight splitting optical system 12, and an imaging lens 13.

FIG. 2 is a perspective view showing an example of the configuration ofthe light splitting optical device 7. As shown in the same figure, thelight splitting optical device 7 is configured as internally equippedwith the collimator lens 11, the imaging lens 13, and the lightsplitting optical system 12 including a front dichroic mirror 25 a, arear dichroic mirror 25 b, a front mirror 26 a, a rear mirror 26 b, anda correction lens 27, in a housing 22. Furthermore, an aperture stop 10with a circular aperture is provided in an end face at one end side ofthe housing 22. This aperture stop 10 has a stop adjusting mechanism 15capable of variably setting the inside diameter of its aperture. Thebelow will describe configurations of the respective constituentelements of the light splitting optical device 7.

This light splitting optical device 7 is arranged so that theobservation light B₁ having passed through the beam splitter 6 can enterthe inside through the aperture stop 10. The observation light B₁ havingpassed through the aperture stop 10 is then converted into parallellight by the collimator lens 11 and the resultant parallel light isoutput along the optical axis L₁ of the collimator lens 11.

The front dichroic mirror 25 a and the rear dichroic mirror 25 b arearranged so as to be detachable from on the optical axis L₁ inside thehousing 22. Namely, these dichroic mirrors 25 a, 25 b are integrallyconfigured so as to be detachable from on the optical path of theobservation light B₁ inside the housing 22. The dichroic mirrors 25 a,25 b may also be integrated with the below-described front mirror 26 a,rear mirror 26 b, and correction lens 27 so as to be detachabletogether. This front dichroic mirror 25 a disperses the parallel lightoutput from the collimator lens 11 and transmits a first split beam B₂dispersed, into a direction along the optical axis L₁. At the same time,the front dichroic mirror 25 a disperses the parallel light and reflectsa second split beam B₃ dispersed, into a direction perpendicular to theoptical axis L₁.

The rear dichroic mirror 25 b further transmits the first split beam B₂having transmitted by the front dichroic mirror 25 a, thereby to outputthe first split beam B₂ toward the imaging lens 13 arranged at the otherend side of the housing 22. At the same time, the rear dichroic mirror25 b reflects the second split beam B₃, which has traveled via the frontmirror 26 a, correction lens 27, and rear mirror 26 b after having beenreflected by the front dichroic mirror 25 a, to output the second splitbeam B₃ toward the imaging lens 13.

The front mirror 26 a reflects the second split beam B₃ output from thefront dichroic mirror 25 a, into a direction parallel to the opticalaxis L₁. The rear mirror 26 b reflects the second split beam B₃ havingtraveled via the front mirror 26 a, along a direction intersecting withthe optical axis L₁ toward a light receiving surface of the reardichroic mirror 25 b. The correction lens 27 is arranged between thefront mirror 26 a and the rear mirror 26 b and has a function toimplement magnification correction and color correction for the secondsplit beam B₃.

The imaging lens 13 is supported so that its optical axis L₂ is parallelto the optical axis L₁ and is configured so that the optical axis L₂ canbe moved in a direction perpendicular to the optical axis L₁ while beingkept in parallel with the optical axis L₁. The imaging lens 13 receivesthe first and second split beams B₂, B₃ split off from the observationlight B₁ via the dichroic mirrors 25 a, 25 b and focuses those splitbeams B₂, B₃ to form separate first and second optical images on theimaging device 8 in a camera device 30 arranged outside. At this time,the inside diameter of the aperture stop 10, the angle and position ofthe rear dichroic mirror 25 b or the rear mirror 26 b, and the positionof the imaging lens 13 are appropriately adjusted, whereby the first andsecond optical images can be made to be received in two divided regionson a light receiving surface of the imaging device 8. On the other hand,when the dichroic mirrors 25 a, 25 b are detached, the imaging lens 13receives the observation light B₁ via the collimator lens 11 only andfocuses the observation light B₁ to form a single optical image on theimaging device 8 in the camera device 30. At this time, the insidediameter of the aperture stop 10 and the position of the imaging lens 13are appropriately adjusted, whereby the single optical image can be madeto be received in a wider region of the entire light receiving surfaceof the imaging device 8.

The light splitting optical device 7 may be provided with a detectionmechanism 14, such as a switch element or a sensor element, whichdetects attachment/detachment of the front dichroic mirror 25 a and therear dichroic mirror 25 b and which outputs a detection signal thereofto the control unit 9. A wavelength filter such as a bandpass filter maybe located on the optical paths of the first and second split beams B₂,B₃ split off from the observation light B₁ via the dichroic mirrors 25a, 25 b.

The light splitting optical device 7 of the configuration as describedabove can be used in common to both of an observation mode to observethe observation light as a single optical image by the camera device 30(which will be referred to hereinafter as “single view mode”) and anobservation mode to observe the observation light as two separateoptical images by the camera device 30 (which will be referred tohereinafter as “double view mode”).

The following will describe the detailed configuration of the imagingdevice 8, with reference to FIG. 3. As shown in the same figure, theimaging device 8 has a plurality of pixel circuits 42 arrayed in atwo-dimensional pattern along its light receiving surface 41. This pixelcircuit 42 is composed of a photodiode 43 for converting light into anelectric charge, an amplifier 44 for converting the electric chargeaccumulated in the photodiode 43, into an electric signal, and a switch45 for defining the readout timing of the electric signal to be outputfrom the amplifier. The plurality of such pixel circuits 42 are arrangedin a predetermined number at predetermined intervals in one direction(the horizontal direction in FIG. 3) along the light receiving surface41 to constitute pixel rows 46. Furthermore, a plurality of pixel rows46 are arranged in juxtaposition in a direction (the vertical directionin FIG. 3) perpendicular to the one direction along the light receivingsurface 41 to constitute adjacent two pixel row groups 47 a, 47 b.Namely, the two pixel raw groups 47 a, 47 b include the pixel rows 46 inrespective regions 48 a, 48 b obtained by dividing the light receivingsurface 41 into two by a central part, out of the plurality of pixelrows 46 arranged across the central part of the light receiving surface41. The regions 48 a, 48 b of this light receiving surface 41 correspondto image formation positions of the first and second optical images,respectively, output from the light splitting optical device 7.

Furthermore, the imaging device 8 has separate circuit configurationscapable of implementing rolling readout for the two pixel row groups 47a, 47 b, respectively. Specifically, series circuits each of whichincludes a CDS amplifier 49 a and an A/D converter 50 a are connected tooutputs of the amplifiers 44 of the respective pixel circuits 42included in the region 48 a and, these series circuits are provided asmany as the number of pixel circuits 42 arranged in each pixel row 46,and are connected thereto in common along an array direction of thepixel rows 46 across the plurality of pixel rows 46 included in thepixel row group 47 a. A common digital signal output circuit (signalreadout circuit) 51 a is connected to these series circuits. Asconfigured in this manner, detection signals of the optical imagedetected by the pixel circuits 42 constituting the pixel rows 46included in the pixel row group 47 a are sequentially read out asdigital signals in units of the respective pixel rows 46 by the digitalsignal output circuit 51 a.

Similarly, series circuits each of which includes a CDS amplifier 49 band an A/D converter 50 b are connected to outputs of the amplifiers 44of the respective pixel circuits 42 included in the region 48 b, andthese series circuits are connected thereto in common along the arraydirection of the pixel rows 46 across the plurality of pixel rows 46included in the pixel row group 47 b. A common digital signal outputcircuit (signal readout circuit) 51 b is connected to these seriescircuits. As configured in this manner, detection signals of the opticalimage detected by the pixel circuits 42 constituting the pixel rows 46included in the pixel row group 47 b are sequentially read out asdigital signals in units of the respective pixel rows 46 by the digitalsignal output circuit 51 b.

The imaging device 8 is further provided with a scan circuit 52 fordefining exposure timings and signal readout timings in the pixelcircuits 42. This scan circuit 52 defines the readout timing of theelectric signals by the switches 45 of the pixel circuits 42, for eachof the pixel rows 46. Namely, the scan circuit 52 defines the readouttiming to implement so-called rolling readout in such a manner that thereadout of the electric signals from the pixel circuits 42 is carriedout in order in a predetermined direction along the light receivingsurface 41 in units of the respective pixel rows 46. In this regard, thescan circuit 52 defines the readout timings so as to perform independentrolling readout in the pixel row group 47 a included in the region 48 aand in the pixel row group 47 b included in the region 48 b.Furthermore, the scan circuit 52 is configured so as to be able to setdirections of the rolling readout along the light receiving surface 41,independently for the pixel row group 47 a included in the region 48 aand for the pixel row group 47 b included in the region 48 b, withreception of an instruction signal from the control unit 9.

Referring back to FIG. 1, the control unit 9 is connected to the imagingdevice 8 and generates an instruction signal to independently controlthe direction of the rolling readout from the pixel row group 47 a inthe imaging device 8 and the direction of the rolling readout from thepixel row group 47 b in the imaging device 8. This control unit 9 may bea control device such as a computer terminal connected outside thecamera device 30, or may be a control circuit mounted on the imagingdevice 8. Specifically, when the light splitting optical device 7 is setin the double view mode, i.e., when the light splitting optical system12 (FIG. 2) including the front dichroic mirror 25 a and the reardichroic mirror 25 b is arranged on the optical path of the observationlight B₁, the control unit 9 performs the control as follows.Specifically, the control is performed in such a manner that thedirection of the rolling readout in the pixel row group 47 a and themethod of the rolling readout in the pixel row group 47 b are identicalin the juxtaposition direction of the pixel rows 46. FIG. 4 is a drawingconceptually showing the directions of the rolling readout in the pixelrow groups 47 a, 47 b on the light receiving surface 41 controlled bythe control unit 9. In this way, the direction of the rolling readout inthe pixel row group 47 a is controlled to the direction (downwarddirection in FIG. 4) from the end of the region 48 a opposite to theregion 48 b to the boundary between the region 48 a and the region 48 b,and the direction of the rolling readout in the pixel row group 47 b iscontrolled to the direction (downward direction in FIG. 4) from theboundary between the region 48 b and the region 48 a to the end of theregion 48 b opposite to the region 48 a.

When the light splitting optical device 7 is set in the single viewmode, i.e., when the light splitting optical system 12 (FIG. 2)including the front dichroic mirror 25 a and the rear dichroic mirror 25b is detached from on the optical path of the observation light B₁, thecontrol unit 9 performs the control as follows. Specifically, thecontrol is performed in such a manner that the direction of the rollingreadout in the pixel row group 47 a and the method of the rollingreadout in the pixel row group 47 b are opposite in the juxtapositiondirection of the pixel rows 46. FIG. 5 is a drawing conceptually showingthe directions of the rolling readout in the pixel row groups 47 a, 47 bon the light receiving surface 41 controlled by the control unit 9. Inthis way, the direction of the rolling readout in the pixel row group 47a is controlled to the direction (upward direction in FIG. 4) from theboundary between the region 48 a and the region 48 b to the end of theregion 48 a opposite to the region 48 b, and the direction of therolling readout in the pixel row group 47 b is controlled to thedirection (downward direction in FIG. 4) from the boundary between theregion 48 b and the region 48 a to the end of the region 48 b oppositeto the region 48 a.

In this regard, when the light splitting optical device 7 is providedwith the detection mechanism for detecting attachment/detachment of thefront dichroic mirror 25 a and the rear dichroic mirror 25 b, thecontrol unit 9 may perform the control so as to switch the readout modeas follows. Namely, with detection of arrangement in which the lightsplitting optical system 12 including the front dichroic mirror 25 a andthe rear dichroic mirror 25 b is arranged on the optical path, thecontrol unit 9 perform the control so as to automatically switch thereadout mode to the first readout mode in which the directions of therolling readout in the pixel row groups 47 a, 47 b are identical asshown in FIG. 4. On the other hand, with detection of arrangement inwhich the light splitting optical system 12 is detached from on theoptical path, the control unit 9 performs the control so as toautomatically switch the readout mode to the second readout mode inwhich the directions of the rolling readout in the pixel row groups 47a, 47 b are opposite as shown in FIG. 5. If the light splitting opticaldevice 7 is not provided with the detection mechanism, the control unit9 may be configured to switch the readout mode in accordance withobserver's selection.

Next, a procedure of a light observation method according to the presentembodiment with the use of the light observation device 1 will bedescribed in detail. FIG. 6 is a flowchart showing the procedure of thelight observation method.

With a start of the observation process, the observer first selects theobservation mode, in order to determine the rolling readout directions(S0). Specifically, the observer selects the single view mode or thedouble view mode, using a selection screen displayed on a display partof the control unit 9. When the double view mode is selected, theobservation light B₁ is split into the first split beam B₂ and thesecond split beam B₃ by the light splitting optical system 12 (S11).Thereafter, the first split beam B₂ and the second split beam B₃ arefocused to form the first optical image corresponding to the first splitbeam B₂ and the second optical image corresponding to the second splitbeam B₃ (S21). The imaging device 8 is arranged so that the pixel rowgroup 47 a is located at the position where the first optical image isformed and so that the pixel row group 47 b is located at the positionwhere the second optical image is formed. In the case of the double viewmode, the control unit selects the first readout mode in which thedirections of the rolling readout in the pixel row group 47 a and in thepixel row group 47 b are identical, and the first optical image and thesecond optical image are captured in the first readout mode (S31). Basedon image data obtained, a first image corresponding to the first opticalimage and a second image corresponding to the second optical image arecreated and displayed on the display part of the control unit 9 (S4).

On the other hand, when the single view mode is selected, theobservation light B₁ is focused to form a optical image (S22). In thecase of the single view mode, the control unit selects the secondreadout mode in which the directions of the rolling readout in the pixelrow group 47 a and in the pixel row group 47 b are opposite, and theoptical image is captured in the second readout mode (S32). Based onimage data obtained by the capturing, an image corresponding to theoptical image is created and displayed on the display part of thecontrol unit 9 (S4).

According to the light observation device 1, the imaging device 8 usedfor the same, and the light observation method as described above, thelight splitting optical system 12 splits the observation light of theobservation object A into the first and second split beams, the firstand second split beams thus split are focused by the imaging lens 13 toform the first and second optical images, the first optical image isreceived by the pixel row group 47 a included in the region 48 a of theimaging device 8, and the second optical image is received by the pixelrow group 47 b included in the region 48 b of the imaging device 8.Then, under control of the control unit 9, detection signals of thefirst and second optical images are read out by independent rollingreadout from the pixel row groups 47 a, 47 b, respectively, while thedirection of the rolling readout in the pixel row group 47 a and thedirection of the rolling readout in the pixel row group 47 b are madeidentical. This makes it easier to match the exposure timings at thesame part of the observation object A between the detected image of thefirst optical image and the detected image of the second optical image,whereby the exposure conditions for each part of the two optical imagescan be made uniform. As a result, it can facilitate comparativeobservation using the detected images of the two optical images.

FIG. 7(a) conceptually shows the directions of the rolling readout onthe light receiving surface 41 controlled by the control unit 9 in usein the double view mode and, in correspondence to it, FIG. 7(b) showsthe exposure timings in the respective pixel rows 46 on the lightreceiving surface 41 in use in the double view mode. As shown in thesame figure, the directions of the rolling readout in the region 48 aand in the region 48 b are set to be identical, whereby exposuredurations T_(A1) of the plurality of pixel rows 46 included in theregion 48 a are set as sequentially delayed each by a predeterminedperiod from the end of the region 48 a toward the central part of thelight receiving surface 41 and whereby exposure durations T_(B1) of theplurality of pixel rows 46 included in the region 48 b are set assequentially delayed each by a predetermined period from the centralpart of the light receiving surface 41 toward the end of the region 48b. As a result, the exposure durations T_(A1), T_(B1) of the pixel rows46 corresponding to the same part of the detected images become easierto be matched between the regions 48 a, 48 b. This allows accuratecomparison between the detected image of the first optical image and thedetected image of the second optical image, in a situation where theobservation object A is in motion, or in a situation where theobservation light varies due to color fading of a fluorescence reagentor the like.

In the configuration herein, the control unit 9 is configured so as tobe able to switch the readout mode between the first readout mode andthe second readout mode. The digital signal output circuits 51 a, 51 band the scan circuit 52 operate so as to select the readout mode fromthe first readout mode and the second readout mode, under control of thecontrol unit 9. This allows the exposure conditions for each part of thetwo optical images in use in the double view mode to be made uniform. Onthe other hand, in use in the single view mode, a linear contrastdifference can be prevented from appearing in a detected image of asingle optical image. As a result, observation of optical image can beimplemented with high accuracy, even in the case where the device is incommon use in the single view mode and the double view mode.

FIG. 8(a) conceptually shows the directions of the rolling readout onthe light receiving surface 41 controlled by the control unit 9 in usein the single view mode and, in correspondence to it, FIG. 8(b) showsthe exposure timings in the respective pixel rows 46 on the lightreceiving surface 41 in use in the single view mode. As shown in thesame figure, the directions of the rolling readout in the region 48 aand in the region 48 b are set to be opposite, whereby exposuredurations T_(A2) of the plurality of pixel rows 46 included in theregion 48 a are set as sequentially delayed each by a predeterminedperiod from the central part of the light receiving surface 41 towardthe end of the region 48 a and whereby exposure durations T_(B2) of theplurality of pixel rows 46 included in the region 48 b are set assequentially delayed each by a predetermined period from the centralpart of the light receiving surface 41 toward the end of the region 48b. As a result, the exposure durations T_(A2), T_(B2) of the pixel rows46 adjacent in the central part of the detected image become easier tobe matched between the regions 48 a, 48 b. This can prevent a linearcontrast difference from appearing at the boundary between the region 48a and the region 48 b in the detected image of the single optical image.

In contrast to it, FIG. 12 shows the exposure timings in the respectivepixel rows 46 on the light receiving surface 41 in a case of settingwhere the device in use in the single view mode is set in the firstreadout mode in which the directions of the rolling readout in the pixelrow groups 47 a, 47 b are identical. With this setting, exposuredurations T_(A3), T_(B3) of the adjacent two pixel rows 46 correspondingto the central part of the detected image become unmatched between theregions 48 a, 48 b, and it is thus unfavorable. In this case, a linearcontrast difference becomes more likely to appear at the boundarybetween the region 48 a and the region 48 b in the detected image of thesingle optical image.

Furthermore, FIG. 13 shows the exposure timings in the respective pixelrows 46 on the light receiving surface 41 in a case using the imagingdevice of the conventional rolling readout method. In this case, therolling readout is executed in one direction over the entire lightreceiving surface 41, whereby exposure durations T₄ of the plurality ofpixel rows 46 are set so as to be sequentially delayed each by apredetermined period from one end to the other end of the lightreceiving surface 41. As a result, when it is used in the double viewmode, the exposure durations T₄ of the pixel rows 46 corresponding tothe same part of the two detected images tend to be unmatched. Becauseof this, the exposure conditions for the detected image of the firstoptical image and for the detected image of the second optical imagebecome different in the situation where the observation object A is inmotion or in the situation where the observation light varies due tocolor fading of a fluorescence reagent or the like, so as to result infailure in accurate comparison between them.

FIG. 14 shows the exposure timings in the respective pixel rows 46 onthe light receiving surface 41 in a case of setting where the device inuse in the double view mode is set in the second readout mode. In thiscase, exposure durations T_(A5), T_(B5) of the adjacent two pixel rows46 corresponding to the same part of the detected images becomeunmatched between the regions 48 a, 48 b. This makes the exposureconditions different between the detected image of the first opticalimage and the detected image of the second optical image, so as toresult in failure in accurate comparison between them.

It should be noted that the present invention is by no means intended tobe limited only to the above-described embodiment.

For example, the first and second readout modes set by the control unit9 of the light observation device 1 can be modified as described below.

FIG. 9 and FIG. 10 are drawings conceptually showing the directions ofthe rolling readout in the pixel row groups 47 a, 47 b on the lightreceiving surface 41 controlled by the control unit 9 according to amodification example of the present invention. As shown in FIG. 9, inuse in the double view mode, the directions of the rolling readout inthe pixel row groups 47 a, 47 b both may be set to the oppositedirections to the directions shown in FIG. 4. Furthermore, in use in thesingle view mode, as shown in FIG. 10, the directions of the rollingreadout in the pixel row groups 47 a, 47 b both may be set to theopposite directions to the directions shown in FIG. 5.

The control unit 9 may be configured so as to allow the exposure timesto be made independently variable for the respective pixel row groups 47a, 47 b, or may be configured so as to be able to control the exposuretimes to different times for the respective pixel row groups 47 a, 47 b.FIG. 11 shows the exposure timings in the respective pixel rows 46 onthe light receiving surface 41 in a modification example of the presentinvention. As shown in the same figure, the control unit 9 can controlthe directions of the rolling readout for the respective pixel rowgroups 47 a, 47 b and can set lengths of the exposure durations T_(A6),T_(B6) of the respective pixel row groups 47 a, 47 b to different times.In this case, the start timing of signal readout of each pixel row 46 isset immediately after the exposure duration T_(A6), T_(B6) of each pixelrow and the start timings of signal readout are controlled so as to besynchronized between the regions 48 a, 48 b. Namely, the timings ofsignal readout of the two pixel rows 46 in the regions 48 a, 48 bcorresponding to the same part of the detected images are controlled soas to be synchronized with each other.

In imaging of the observation light in the conventional double viewmode, the optical images in different wavelength regions areindividually captured and if the light intensities of the respectiveoptical images are significantly different, the light is made to passthrough a neutral density filter or the like so as to approximatelyequalize the light intensities. In the present embodiment shown in FIG.11, the exposure times can be set independently between the two opticalimages and, thus, the exposure time for one optical image with thelarger light intensity can be set shorter than that for the other,whereby the light intensities detected as detected images can beapproximately equalized without use of the neutral density filter.Furthermore, by synchronizing the timings of signal readout of the twopixel rows 46 in the two regions 48 a, 48 b, the exposure timings can besurely matched for the same part of the observation object between thedetected images of the two optical images, whereby the exposureconditions for the same part of the two optical images can be made moreuniform.

The configuration of the light splitting optical device 7 forming thelight observation device 1 is not limited only to the configurationshown in FIG. 2, but it may be configured using the conventionalconfigurations such as the light splitting optical systems described inthe U.S. Pat. No. 5,926,283 and U.S. Pat. No. 7,667,761 and the opticalsystem described in Literature “K. Kinosita, Jr. et al., “Dual ViewMicroscopy with a Single Camera: Real-Time Imaging of MolecularOrientations and Calcium,” The Journal of Cell Biology, Volume 115,Number 1, October 1991, pp 67-73.” Furthermore, the light splittingoptical system 12 is not limited only to the configuration including thedichroic mirrors.

It is preferred herein that in the above-described light observationdevice, the control unit perform the control so as to allow switchingbetween: a first readout mode in which the direction of the rollingreadout in the first pixel row group and the direction of the rollingreadout in the second pixel row group are identical in the juxtapositiondirection of the plurality of pixel rows; and a second readout mode inwhich the direction of the rolling readout in the first pixel row groupand the direction of the rolling readout in the second pixel row groupare opposite in the juxtaposition direction of the plurality of pixelrows. Furthermore, it is preferred that in the above-described lightobservation method, selection be implemented between: a first readoutmode in which the direction of the rolling readout in the first pixelrow group and the direction of the rolling readout in the second pixelrow group are identical in the juxtaposition direction of the pluralityof pixel rows; and a second readout mode in which the direction of therolling readout in the first pixel row group and the direction of therolling readout in the second pixel row group are opposite in thejuxtaposition direction of the plurality of pixel rows. By adopting sucha configuration, the readout mode is switched to the first readout modein simultaneous imaging of the two optical images by the imagingelement, whereby the exposure conditions for each part of the twooptical images can be made uniform. On the other hand, the readout modeis switched to the second readout mode in imaging of the single opticalimage by the imaging element, whereby a linear contrast difference canbe prevented from appearing in the detected image of the single opticalimage. As a result, it becomes feasible to implement high-accuracyobservation of optical image, even in the case where the device is usedin common in the observation mode to image the two optical images and inthe observation mode to image the single optical image.

Furthermore, it is also preferred that the light splitting opticalsystem be configured so as to be detachable from on an optical path ofthe observation light and that the control unit perform the control soas to switch to the first readout mode when the light splitting opticalsystem is arranged on the optical path and to switch to the secondreadout mode when the light splitting optical system is detached from onthe optical path. In this case, since the control is performed so as toswitch between the first and second readout modes in accordance withattachment/detachment of the light splitting optical system,high-accuracy observation of optical image is facilitated in the casewhere the device is used in common in the observation mode to image thetwo optical images and in the observation mode to image the singleoptical image.

Furthermore, it is also preferred that the control unit perform thecontrol so as to allow each of an exposure time of the rolling readoutin the first pixel row group and an exposure time of the rolling readoutin the second pixel row group to be made variable. This allows thesensitivity in imaging of the first optical image and the sensitivity inimaging of the second optical image to be freely set, so as to enhancedegrees of freedom of the imaging conditions for the two optical images.

Yet furthermore, it is also preferred that the control unit perform thecontrol so as to set an exposure time of the rolling readout in thefirst pixel row group and an exposure time of the rolling readout in thesecond pixel row group to different times. This allows the sensitivityin imaging of the first optical image and the sensitivity in imaging ofthe second optical image to be set to be different, so as to enhancedegrees of freedom of the imaging conditions for the two optical images.

Still furthermore, it is also preferred that the control unit performthe control so as to synchronize a start timing of the rolling readoutin the first pixel row group with a start timing of the rolling readoutin the second pixel row group. This configuration allows the exposuretimings at the same part of the object to be surely matched between thedetected image of the first optical image and the detected image of thesecond optical image, so as to further uniformize the exposureconditions for each part of the two optical images.

It is also preferred herein that in the foregoing imaging device, thefirst and second signal readout circuits implement switching between: afirst readout mode in which the direction of the rolling readout in thefirst pixel row group and the direction of the rolling readout in thesecond pixel row group are identical in the juxtaposition direction ofthe plurality of pixel rows; and a second readout mode in which thedirection of the rolling readout in the first pixel row group and thedirection of the rolling readout in the second pixel row group areopposite in the juxtaposition direction of the plurality of pixel rows.By adopting such a configuration, the readout mode is switched to thefirst readout mode in simultaneous imaging of the two optical images bythe imaging element, whereby the exposure conditions for each part ofthe two optical images can be made uniform. On the other hand, thereadout mode is switched to the second readout mode in imaging of thesingle optical image by the imaging element, whereby a linear contrastdifference can be prevented from appearing in the detected image of thesingle optical image. As a result, it becomes feasible to implementhigh-accuracy observation of optical image, even in the case where thedevice is used in common in the observation mode to image the twooptical images and in the observation mode to image the single opticalimage.

INDUSTRIAL APPLICABILITY

The present invention is applied to usage as the light observationdevice for observing the optical image of the object, the imaging deviceused for the same, and the light observation method and facilities thecomparative observation between two types of optical images of theobject even in the case adopting the rolling readout method.

REFERENCE SIGNS LIST

1 light observation device; 7 light splitting optical device; 8 imagingdevice; 9 control unit; 12 light splitting optical system; 13 imaginglens; 42 pixel circuit; 46 each pixel row; 47 a first pixel row group;47 b second pixel row group; 48 a first region; 48 b second region; 51 adigital signal output circuit (first signal readout circuit); 51 bdigital signal output circuit (second signal readout circuit); Aobservation object; B₁ observation light; B₂ first split beam; B₃ secondsplit beam.

1. A light observation device comprising: a light splitting opticalsystem configured to receive observation light of an object from theoutside and split the observation light into first and second beams; animaging lens configured to receive the first and second beams and focusthe first and second beams to form first and second optical images; animaging element which is arranged at image formation positions of thefirst and second optical images, which is configured with a plurality ofpixel rows including a plurality of pixels and being arranged injuxtaposition, and which can perform independent rolling readout in afirst pixel row group among a plurality of pixel rows included in afirst region corresponding to the image formation position of the firstoptical image and in a second pixel row group among a plurality of pixelrows included in a second region corresponding to the image formationposition of the second optical image; and a control unit configured tocontrol the rolling readout in the first pixel row group included in thefirst region and in the second pixel row group included in the secondregion, wherein the control unit performs control such that a directionof the rolling readout in the first pixel row group and a direction ofthe rolling readout in the second pixel row group are identical in ajuxtaposition direction of the plurality of pixel rows.
 2. The lightobservation device according to claim 1, wherein the control unitperforms the control so as to allow switching between: a first readoutmode in which the direction of the rolling readout in the first pixelrow group and the direction of the rolling readout in the second pixelrow group are identical in the juxtaposition direction of the pluralityof pixel rows; and a second readout mode in which the direction of therolling readout in the first pixel row group and the direction of therolling readout in the second pixel row group are opposite in thejuxtaposition direction of the plurality of pixel rows.
 3. The lightobservation device according to claim 2, wherein the light splittingoptical system is configured so as to be detachable from on an opticalpath of the observation light, and wherein the control unit performs thecontrol so as to switch to the first readout mode when the lightsplitting optical system is arranged on the optical path and to switchto the second readout mode when the light splitting optical system isdetached from on the optical path.
 4. The light observation deviceaccording to claim 1, wherein the control unit performs the control soas to allow each of an exposure time of the rolling readout in the firstpixel row group and an exposure time of the rolling readout in thesecond pixel row group to be made variable.
 5. The light observationdevice according to claim 1, wherein the control unit performs thecontrol so as to set an exposure time of the rolling readout in thefirst pixel row group and an exposure time of the rolling readout in thesecond pixel row group to different times.
 6. The light observationdevice according to claim 1, wherein the control unit performs thecontrol so as to synchronize a start timing of the rolling readout inthe first pixel row group with a start timing of the rolling readout inthe second pixel row group.
 7. An imaging device to be used for a lightobservation device which splits observation light of an object from theoutside into first and second beams and which simultaneously capturesfirst and second optical images generated based on the first and secondbeams, the imaging device comprising: a first pixel row group configuredwith a plurality of pixel rows including a plurality of pixels and beingarranged in juxtaposition; a second pixel row group adjoining the firstpixel row group and configured with a plurality of pixel rows includinga plurality of pixels and being arranged in juxtaposition; a firstsignal readout circuit for processing signal readout from the firstpixel row group; and a second signal readout circuit for processingsignal readout from the second pixel row group, independently of thefirst signal readout circuit, wherein the first signal readout circuitprocesses the signal readout in the first pixel row group by rollingreadout and sets a direction of the rolling readout to one direction ina juxtaposition direction of the plurality of pixel rows, and whereinthe second signal readout circuit processes the signal readout in thesecond pixel row group by rolling readout and sets a direction of therolling readout to the one direction in the juxtaposition direction ofthe plurality of pixel rows.
 8. The imaging device according to claim 7,wherein the first and second signal readout circuits implement switchingbetween: a first readout mode in which the direction of the rollingreadout in the first pixel row group and the direction of the rollingreadout in the second pixel row group are identical in the juxtapositiondirection of the plurality of pixel rows; and a second readout mode inwhich the direction of the rolling readout in the first pixel row groupand the direction of the rolling readout in the second pixel row groupare opposite in the juxtaposition direction of the plurality of pixelrows.
 9. A light observation method using an imaging device which has afirst pixel row group configured with a plurality of pixel rowsincluding a plurality of pixels and being arranged in juxtaposition, anda second pixel row group adjoining the first pixel row group andconfigured with a plurality of pixel rows including a plurality ofpixels and being arranged in juxtaposition and which can perform rollingreadout in each of the first pixel row group and the second pixel rowgroup, the image observation method comprising: splitting observationlight of an object from the outside into first and second beams;focusing the first beam to form a first optical image so as to impingeon the first pixel row group; focusing the second beam to form a secondoptical image so as to impinge on the second pixel row group; andperforming control such that a direction of the rolling readout in thefirst pixel row group and a direction of the rolling readout in thesecond pixel row group are identical in a juxtaposition direction of theplurality of pixel rows.
 10. The light observation method according toclaim 9, comprising: implementing selection between a first readout modein which the direction of the rolling readout in the first pixel rowgroup and the direction of the rolling readout in the second pixel rowgroup are identical in the juxtaposition direction of the plurality ofpixel rows; and a second readout mode in which the direction of therolling readout in the first pixel row group and the direction of therolling readout in the second pixel row group are opposite in thejuxtaposition direction of the plurality of pixel rows.